Entanglement is one of the most captivating topics in quantum physics – at least, that’s the case for those of us who majored in the liberal arts. The simple explanation is that whenever two things interact, they are forever connected no matter the distance between them. Physicists, of course, explain it with different words and the concept is considerably more complicated than my definition makes it seem.

The theory, which turned quantum physics on its head and drove scientists like Einstein to distraction, did not spring from the mind of a single scientist but evolved through time and through the give and take of many experiments and conversations. The Age of Entanglement is “a book of conversations,” as author Louisa Gilder explains. Every chat fest that led to the development of an understanding of entanglement is not recorded, of course. Gilder approximates the process by drawing from documented sources – journals, letters, articles—and then enhances the process with creative linking; that is, she combines the solid facts with likely settings and segues, filling in the blanks with imagined details. Purists may complain that the line between fact and fiction is blurred, but Gilder’s imaginative narrative is at least as legitimate as scientific musing.

The Age of Entanglement makes it clear that scientific progress is not a linear progression and that it is considerably messier than the precise mathematical formulas make it seem. Gilder’s characterization of the physicists involved (and that’s most of the ones you’ve heard of) reveal not only their purely human quirks and flaws but also their passionate pursuit of answers. Far from dry, plodding stereotypes, Gilder gives us human beings who delight in ferreting out answers, finding the obsessive search as normal and necessary as breathing.

Like the particles they studied, these scientists are entangled as they alternately deny or support each others’ work. Egos and hero worship abound as witnessed by the documented comments, and the relationships are made clearer by Gilder’s fictional contributions. Pulling in, as it must, most of those who led the field forward – Bohm, Bohr, Schroedinger, and of course, Bell—Gilder helps readers understand how the leaps were made. For example, she proposes a conversation between John Bell and his wife, Mary, in 1963, addressing Bell’s examination of Josef Jauch’s take on von Neumann’s theorem that banned hidden variables in the entanglement argument.

“Well, you know, it’s very strange,” said John, looking up from his desk for the first time in hours. “I’ve just been playing around with a simple system of two spin-1/2 particles…. Not trying to be very serious, you know, but just to get some simple relations between input and output that might give a local account of the quantum correlations….”

“So you’ve returned to von Neumann,” she said, smiling.

It’s the personal touches, the domestic interactions, even the silliness of brilliant minds in relaxed moments that give The Age of Entanglement a charm that makes the geniuses and their accomplishments so impressive.

The purpose of Gilder’s book is to trace the history of entanglement, but the personalities are a critical component of that history. Without those minds, after all, there would be no theory – at least, not the theory we have. Gilder does a masterful job of filling out the empty spaces, showing us why these people in particular made those specific leaps. Just as in a well-written novel, the process as it is presented in The Age of Entanglement leads to an inevitable outcome.

Gilder’s collection of sources seems overwhelming, but she manages to wrangle them into a sensible and understandable order that even the average reader will be able to follow; scientists, too, should be able to appreciate this unique approach to history. It’s just plain fun to eavesdrop on the conversations, whether real or imagined, and one hopes the author will continue to explore such alternative means toward educating the public about the work that goes on inside scientific minds.